The present invention relates to kneading machines for food doughs, particularly for bakery products, of the type comprising a substantially cylindrical tank and a pair of kneading implements turning within the tank, with concordant directions of rotation, about two axes that are substantially parallel to the axis of the tank and are set at a distance from the axis of the tank, so as to describe two theoretical cylinders that are substantially tangential both with respect to one another, and with respect to the circumferential wall of the tank.
A kneading machine of the type indicated above is described and illustrated in the European patent EP OR 354 190 B1 and in the corresponding U.S. Pat. No. 4,919,539 in the name of the present applicant. In said machine, the two kneading implements are in the form of helical spirals that wind about a theoretical cylindrical surface through an angle considerably greater than 180° and in a typical case even greater than 360°, which corresponds to a situation in which the axial dimension of the kneading implement is close to the value of the pitch of the helical spiral.
Even though the aforesaid known machine has already represented a substantial improvement over more traditional machines, which use a single spiral kneading implement, the present applicant has in any case proceeded with studies and tests aimed at providing a kneading machine, which will be optimal both from the point of view of the quality of the mix obtained and from the point of view of the productivity of the machine, as well as from the point of view of a simplification in design and reduction in the costs for fabrication of the machine itself. In particular, the aim has been to achieve progress in order to reduce the increase in temperature that occurs with the operation of mixing in known machines.